Last updated: February 2026
LA Water Quality Overview
Los Angeles tap water meets all federal and California state drinking water standards — but that's a lower bar than most people realize.
The Los Angeles Department of Water and Power (LADWP) serves approximately 4 million people across the city. According to EWG's analysis of LADWP data, the system has detected multiple contaminants above health guidelines, even while remaining in legal compliance.
LA's water quality challenges stem from its unique situation: the city imports most of its water from hundreds of miles away, blending sources with different quality profiles. The Colorado River supply, in particular, carries higher mineral content and some contaminants picked up across its 1,400-mile journey.
Where LA Water Comes From
Unlike New York City (which has one pristine watershed), LA cobbles together water from three very different sources:
1. Los Angeles Aqueduct (~30%)
Built in 1913, the LA Aqueduct carries snowmelt from the Eastern Sierra Nevada (Owens Valley and Mono Basin) over 200 miles to Los Angeles. This is LA's highest-quality water source — low in minerals and contaminants, similar to NYC's mountain watershed supply.
- Cleanest of LA's three sources
- Low TDS (total dissolved solids)
- Supply varies dramatically with snowpack — drought years mean less aqueduct water
2. Metropolitan Water District (~58%)
The MWD supplies LA with water from two massive systems:
Colorado River (via Colorado River Aqueduct): This 242-mile aqueduct brings water from the Colorado River near Parker Dam. Colorado River water is high in minerals (TDS of 600-700 ppm) because it picks up dissolved salts across seven states. It's also the source of most of LA's elevated contaminant levels.
State Water Project (via California Aqueduct): Delivers water from the Sacramento-San Joaquin Delta in Northern California. Quality is moderate — better than Colorado River but not as clean as the LA Aqueduct.
3. Local Groundwater (~12%)
LADWP operates wells in the San Fernando Valley, Central Basin, and other local aquifers. Groundwater quality varies significantly by location — some wells have been shut down due to PFAS contamination or industrial pollutants.
💡 Why it matters: The blend of sources changes throughout the year. During wet years, more Sierra snowmelt means better overall quality. During drought, more Colorado River water means harder, more mineral-laden water with higher contaminant levels. Your water quality literally changes with the weather.
Contaminants Detected in LA Water
Based on LADWP water quality reports and EWG analysis, here are the key contaminants found in LA tap water:
| Contaminant | LA Level | EPA Limit | EWG Guideline | Status |
|---|---|---|---|---|
| Chromium-6 | 100–500 ppt | No federal limit | 20 ppt | 5–25x above EWG ✗ |
| Haloacetic acids (HAA5) | 15–35 ppb | 60 ppb | 0.1 ppb | 150–350x above EWG ✗ |
| THMs | 20–45 ppb | 80 ppb | 0.15 ppb | 133–300x above EWG ✗ |
| Arsenic | 1–3 ppb | 10 ppb | 0.004 ppb | 250–750x above EWG ✗ |
| Bromate | 2–5 ppb | 10 ppb | 0.1 ppb | 20–50x above EWG ✗ |
| Nitrate | 1–4 mg/L | 10 mg/L | 0.14 mg/L | Above EWG ✗ |
| Uranium | Trace–3 ppb | 30 ppb | 0.43 ppb | Varies by area |
| Chlorine | 1–2.5 mg/L | 4 mg/L | — | Within limits |
| Fluoride | ~0.7 mg/L | 4 mg/L | — | Target level ✓ |
| Lead (90th %ile) | 2–5 ppb | 15 ppb (AL) | 0 ppb | Above EWG ✗ |
Key takeaway: LA water is legally compliant, but EWG analysis shows 8+ contaminants above health guidelines. The biggest concerns are chromium-6 (no federal limit), disinfection byproducts, and arsenic. A reverse osmosis filter addresses all of these.
The Chromium-6 Problem
Chromium-6 (hexavalent chromium) — the "Erin Brockovich chemical" — is one of LA's most significant water quality concerns.
Key facts about chromium-6 in LA water:
- No federal limit exists. The EPA only regulates total chromium at 100 ppb — this includes less harmful chromium-3.
- California tried. The state set a chromium-6 limit of 10 ppb in 2014, but it was withdrawn in 2017 after a legal challenge from the water industry. A new standard is being developed but isn't finalized.
- EWG's health guideline is 20 ppt (parts per trillion) — that's 0.02 ppb. LA's levels are typically 100-500 ppt — 5 to 25 times higher.
- Health effects: The National Toxicology Program classifies chromium-6 as a probable carcinogen when ingested, linked to stomach cancer.
- Source: Both naturally occurring in California groundwater and from industrial contamination. The Colorado River supply also contains elevated levels.
What removes chromium-6? Reverse osmosis is the most effective home treatment, removing 90%+ of chromium-6. Standard carbon filters (Brita, PUR) do not significantly reduce it.
PFAS in LA Water
PFAS (forever chemicals) have been a growing concern for LA-area water:
- Groundwater contamination: Several LADWP wells in the San Fernando Valley have been shut down or treated due to PFAS contamination, particularly near former military bases and industrial sites.
- Surface water: The LA Aqueduct and imported water generally show lower PFAS levels than local groundwater.
- Ongoing monitoring: LADWP is actively testing for PFAS compounds as new federal limits (4 ppt for PFOA/PFOS) take effect.
- Treatment investments: The city has invested in granular activated carbon (GAC) treatment at several groundwater wells to remove PFAS.
LA's Hard Water Issue
If you've ever noticed white scale on your faucets or shower doors in LA, that's hard water. And it's more than cosmetic:
| Water Source | Hardness (ppm) | Classification |
|---|---|---|
| LA Aqueduct (Sierra) | 50–100 | Soft to Moderate |
| State Water Project | 150–250 | Hard |
| Colorado River | 300–400 | Very Hard |
| Local groundwater | 200–500 | Hard to Very Hard |
| Typical LA blend | 200–400 | Hard to Very Hard |
Hard water effects include:
- Scale buildup on fixtures, shower doors, and inside appliances (shortens their lifespan)
- Dry skin and hair — many LA residents notice a difference when traveling to soft-water cities
- Soap scum and reduced soap/detergent effectiveness
- Spotty dishes from mineral deposits
- Water heater efficiency drops as scale builds inside the tank
A whole-house water softener or an RO system at the kitchen sink can address hard water issues.
LA Water vs NYC Water
The two biggest U.S. cities have very different water profiles:
| Factor | Los Angeles | New York City |
|---|---|---|
| Primary source | Colorado River, State Water Project | Catskill/Delaware watershed |
| Source quality | Multiple sources, mixed quality | Protected mountain watershed |
| TDS (hardness) | 200–400 ppm (hard) | 15–40 ppm (soft) |
| Chromium-6 | Elevated ✗ | Low ✓ |
| Disinfection byproducts | Moderate ✗ | Moderate ✗ |
| PFAS risk | Moderate (groundwater) | Low ✓ |
| Taste | Mineral-heavy, chlorine | Clean, low-mineral |
| Overall EWG score | More contaminants above guidelines | Fewer contaminants above guidelines |
Bottom line: NYC has a clear advantage in source water quality. LA's reliance on the Colorado River and multiple blended sources creates more contamination challenges. LA residents benefit more from filtration than most New Yorkers.
Best Filters for LA Water
Given LA's specific contaminant profile (chromium-6, hard water, DBPs, arsenic), here's what we recommend:
APEC ROES-50 Reverse Osmosis
~$200
The best solution for LA's specific contaminants. Removes chromium-6, arsenic, DBPs, PFAS, hard water minerals, and 1,000+ contaminants. 5-stage filtration. Made in USA. Handles LA's hard water without issue.
View on Amazon →iSpring RCC7AK
~$250
6-stage RO with alkaline remineralization stage. Removes LA's hard water minerals and contaminants, then adds back healthy minerals for taste. NSF 58 certified. 75 GPD.
View on Amazon →Waterdrop G3P800
~$700
Tankless RO with instant 800 GPD flow. Smart TDS monitoring faucet. Compact under-sink design. NSF 58 certified. Handles LA's hard water and removes all major contaminants.
View on Amazon →For Hard Water (Whole House)
Fleck 5600SXT Water Softener
~$600
Solves LA's hard water throughout the entire house. Prevents scale on fixtures, appliances, and water heaters. Digital metered regeneration. 48,000 grain capacity.
View on Amazon →Brita Elite Pitcher
~$33
If you just want better-tasting water, a Brita Elite removes chlorine taste and 99% of lead. Won't help with chromium-6, hard water, or PFAS — but it's a start.
View on Amazon →🔬 Not Sure What's in Your LA Tap Water?
Test your specific tap. Utility data shows what leaves the plant — not what reaches your faucet after traveling through your building's plumbing.
Get a Home Water Test Kit →Frequently Asked Questions
Is Los Angeles tap water safe to drink?
LA tap water meets all EPA and California state legal standards. However, EWG analysis shows 8+ contaminants above health guidelines, including chromium-6, disinfection byproducts, and arsenic. It's legally compliant but not as clean as cities like New York. A filter is recommended for improved safety.
What contaminants are in LA tap water?
Key contaminants include chromium-6 (5-25x above EWG guidelines), haloacetic acids and trihalomethanes (disinfection byproducts linked to cancer), arsenic, bromate, and nitrates. LA also has very hard water (200-400 ppm TDS) due to its Colorado River supply.
Where does LA get its water?
Three sources: the LA Aqueduct from the Eastern Sierra (~30%), Metropolitan Water District imports from the Colorado River and State Water Project (~58%), and local groundwater (~12%). The mix changes seasonally and with drought conditions.
Does LA water have PFAS?
PFAS have been detected in some LA-area groundwater wells, particularly near former military bases. Several wells have been shut down. Surface water sources generally show lower PFAS levels. LADWP is actively monitoring and treating as federal limits take effect.
Why is LA water so hard?
LA's hardness comes primarily from the Colorado River, which picks up dissolved minerals (calcium, magnesium) across 1,400 miles and seven states. Colorado River water has 300-400 ppm TDS. When blended with other sources, LA's water typically runs 200-400 ppm — classified as hard to very hard.
What is the best water filter for LA tap water?
A reverse osmosis system is the best choice for LA water. It addresses LA's specific concerns: chromium-6, arsenic, DBPs, PFAS, and hard water minerals. The APEC ROES-50 (~$200) is our top budget pick. Standard carbon filters (Brita, PUR) improve taste but don't remove chromium-6 or arsenic.